Heavy machinery and equipment frequently require repair and it is generally preferable that such repair be done in the “field” rather than transporting the machinery or equipment to a suitable repair facility as this reduces the associated time and costs required for such repair. One of the most commonly required repairs for large machinery or equipment is the repair of a bore, that is, a circular opening that supports an axle or shaft, for example, which becomes damaged or excessively worn due to a variety of different reasons or causes. Alternatively, it may be desired to machine a bore out to a slightly larger diameter for a variety of different reasons. In many repair applications, it is also necessary to form an annular groove or recess, within the bore being repaired, to accommodate a C-clip, a retaining ring, or some other stop member or element.
The repair of a damaged or worn bore typically involves rebuilding the interior surface of the bore by deposition of a metal, typically by a welding or a flame deposition process, followed by the subsequent machining and boring of the rebuilt or refabricated bore to the a precisely required diameter. The rebuilding and machining operations are typically performed in the field by means of a portable boring machine which has a boring bar that is inserted into the bore. The boring bar is typically supported on bearings, on each side of the bore, and may be fitted with a variety of tools for repairing the bore, such as a welding head and a variety of cutting or machining tools, such as a rotatable groove cutting tool or assembly.
A conventional boring bar, along with its associated boring bar bearings supported at each end of the bore, provides the radial support and rigidity for the welding head and/or the tools that are necessary for the accurate reconstruction of a bore, but also presents other problems and shortcomings.
While conventional boring tools, used in combination with the boring bar, are adequate for machining the interior surface of bore to a desired constant diameter, such conventional tools are unable to reliably and accurately form an annular groove within the bore for accommodating, for example, a C-clip, a retaining ring, or some other stop member or element within the bore being repaired. In addition, such conventional tools do not permit indexing a machining or cutting tool, either radially inward to a smaller radius or radially outward to a larger radius, while the boring bar is rotating and/or indexing the machining or cutting tool a desired radial distance following each complete rotation of the boring bar.